Firstly, apologies if this is an oft-asked question, I did do a lot of searching before hand but couldn't find an answer to this, so I'm turning to the community to see if anyone else has any experience of this.
I have a fairly simple, but working, setup with veeam which I've attempted to sketch here:

In short each night I do a backup to a local NAS box and each week I do an offsite backup to a remote NAS box, it works fine.
What I would like to try to do, in order to improve performance, is enable jumbo frames on the local NAS box. This is easy to do in terms of config, I turn on jumbo frames (maybe even iSCSI if I'm feeling brave) and I configure a VLAN on the switch to handle them (it's a ProCurve 5406zl), but then the issue arises: how do I get a 9000MTU port into the veeam machine?
If I replace the existing vNIC / vSwitch and map it all through directly it will work, but then veeam won't have access to the LAN which means it won't be able to perform the weekly offsite backups (and it also means that trying to RDP into the veeam machine will be a real pain). Additionally the NAS box is currently on the LAN and "browsable" in terms of retriving the veeam files, which it wouldn't be if I had to VLAN it off in its entirety.
Presumable if I include an additional vNIC so that I have one on the LAN and one on the new-backup-VLAN, that would work, and if I gave it a different subnet veeam would know that the backup storage was down one NIC and not the other, but is that the best / only way?
What are everyone's thoughts, does anyone actually do this?